/* Copyright (c) 2016, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#ifndef _SDE_FENCE_H_
#define _SDE_FENCE_H_

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/mutex.h>

#ifndef CHAR_BIT
#define CHAR_BIT 8 /* define this if limits.h not available */
#endif

#ifdef CONFIG_SYNC
/**
 * sde_sync_get - Query sync fence object from a file handle
 *
 * On success, this function also increments the refcount of the sync fence
 *
 * @fd: Integer sync fence handle
 *
 * Return: Pointer to sync fence object, or NULL
 */
void *sde_sync_get(uint64_t fd);

/**
 * sde_sync_put - Releases a sync fence object acquired by @sde_sync_get
 *
 * This function decrements the sync fence's reference count; the object will
 * be released if the reference count goes to zero.
 *
 * @fence: Pointer to sync fence
 */
void sde_sync_put(void *fence);

/**
 * sde_sync_wait - Query sync fence object from a file handle
 *
 * @fence: Pointer to sync fence
 * @timeout_ms: Time to wait, in milliseconds. Waits forever if timeout_ms < 0
 *
 * Return: Zero on success, or -ETIME on timeout
 */
int sde_sync_wait(void *fence, long timeout_ms);

/**
 * sde_sync_get_name_prefix - get integer representation of fence name prefix
 * @fence: Pointer to opaque fence structure
 *
 * Return: 32-bit integer containing first 4 characters of fence name,
 *         big-endian notation
 */
uint32_t sde_sync_get_name_prefix(void *fence);
#else
static inline void *sde_sync_get(uint64_t fd)
{
	return NULL;
}

static inline void sde_sync_put(void *fence)
{
}

static inline int sde_sync_wait(void *fence, long timeout_ms)
{
	return 0;
}

static inline uint32_t sde_sync_get_name_prefix(void *fence)
{
	return 0x0;
}
#endif

/**
 * struct sde_fence - output fence container structure
 * @timeline: Pointer to fence timeline
 * @dev: Pointer to drm device structure
 * @commit_count: Number of detected commits since bootup
 * @done_count: Number of completed commits since bootup
 * @fence_lock: Mutex object to protect local fence variables
 */
struct sde_fence {
	void *timeline;
	void *dev;
	int32_t commit_count;
	int32_t done_count;
	struct mutex fence_lock;
};

#if IS_ENABLED(CONFIG_SW_SYNC)
/**
 * sde_fence_init - initialize fence object
 * @dev: Pointer to drm device structure
 * @fence: Pointer to crtc fence object
 * @name: Timeline name
 * Returns: Zero on success
 */
int sde_fence_init(void *dev,
		struct sde_fence *fence,
		const char *name);

/**
 * sde_fence_deinit - deinit fence container
 * @fence: Pointer fence container
 */
void sde_fence_deinit(struct sde_fence *fence);

/**
 * sde_fence_prepare - prepare to return fences for current commit
 * @fence: Pointer fence container
 * Returns: Zero on success
 */
int sde_fence_prepare(struct sde_fence *fence);

/**
 * sde_fence_create - create output fence object
 * @fence: Pointer fence container
 * @val: Pointer to output value variable, fence fd will be placed here
 * @offset: Fence signal commit offset, e.g., +1 to signal on next commit
 * Returns: Zero on success
 */
int sde_fence_create(struct sde_fence *fence, uint64_t *val, int offset);

/**
 * sde_fence_signal - advance fence timeline to signal outstanding fences
 * @fence: Pointer fence container
 * @is_error: Set to non-zero if the commit didn't complete successfully
 */
void sde_fence_signal(struct sde_fence *fence, bool is_error);
#else
static inline int sde_fence_init(void *dev,
		struct sde_fence *fence,
		const char *name)
{
	/* do nothing */
	return 0;
}

static inline void sde_fence_deinit(struct sde_fence *fence)
{
	/* do nothing */
}

static inline void sde_fence_prepare(struct sde_fence *fence)
{
	/* do nothing */
}

static inline int sde_fence_get(struct sde_fence *fence, uint64_t *val)
{
	return -EINVAL;
}

static inline void sde_fence_signal(struct sde_fence *fence, bool is_error)
{
	/* do nothing */
}

static inline int sde_fence_create(struct sde_fence *fence, uint64_t *val,
								int offset)
{
	return 0;
}
#endif /* IS_ENABLED(CONFIG_SW_SYNC) */

#endif /* _SDE_FENCE_H_ */